Michelle Obama and Cindy McCain appear as different as black and white, but both women have multiple higher-education degrees, their own career accomplishments, and have taken bold roles in their husbands' presidential campaigns.
One of these two women will succeed Laura Bush, a former librarian who gave up her career to be a stay-at-home mom and later a quiet presence in the White House.
"Americans are going to get a different first lady," said Melissa Harris-Lacewell, associate professor of politics and African-American studies at Princeton University, and who is friends with Michelle Obama. "Whoever winds up there, it's going to be a different approach."
And both may owe a debt to Hillary Clinton in allowing them to be a more independent and assertive first lady.
In the 1992 presidential campaign, Clinton was lambasted for being such a strong personality that Bill Clinton said voters would get "two for one." Hillary Clinton again became a public pinata for unsuccessfully pushing her health care agenda through Congress.
"The campaigns don't necessarily want the wives to appear overly substantive," said Carl Sferrazza Anthony, a historian for the National First Ladies Library in Canton, Ohio. "The campaign of 1992 stands out as a stark reminder of how a first lady can be demonized if there is the slightest suggestion she might use her intelligence and experience and offer advice to her husband."
But Americans are now ready for a more dynamic first lady, according to Kim Gandy, president of the National Organization for Women.
"There's been a generational shift," Gandy told ABCNews.com. "The reception that Hillary got as an accomplished lawyer in 1992 was far more threatening than either Cindy McCain or Michelle Obama will get in 2008."
Michelle opened the Democrats' convention in Denver last week and Cindy was a stand-in for her husband at the GOP's Twin Cities convention this week.
Michelle Obama would clearly be the history maker, being the first black woman to head the East Wing of the White House, and that would bring added pressures that could temper her behavior.
"The twist is that Cindy McCain has more of an opportunity to make a more radical difference," said Catherine Algore, visiting professor at Claremont McKenna College and author of "A Perfect Union: Dolley Madison and the Creation of the American Nation."
"It's the paradox of her being a Republican woman, with traditional appearance and presence of self. She can actually do more than someone looked at as a radical, liberal feminist and black woman," Algore told ABCNews.com.
"In some ways Michelle Obama is constrained by our own prejudices and expectations, whereas Cindy McCain can take that conservative, former beauty queen wife and mother and philanthropist and run with it," she said.
But either women will have to negotiate her high-powered ego through White House traditions.
History demonstrates that the role of first lady is complex, according to Edward Berkowitz, professor of history and public policy at George Washington University.
"There are contradictions built in to the family and political roles," he told ABCNews.com. "How to reconcile between being active and not getting involved, giving the president the proper space, the proper environment for giving advice, but not definitive advice. The tensions are very hard to navigate."
The wife of Sen. Barack Obama may be called the "black Jackie," with her stylish dress, chunk pearls and attractive young children. But Jackie Kennedy came from a wealthy background and devoted her efforts when first lady to redecorating the White House.
"Michelle Obama is a different animal than any other first lady ever," said Berkowitz. "She is this sort of black, upwardly mobile, upper-class type. She is not that aristocratic, but very often the high-achieving black world has its own rules and … decorum."
Michelle Obama, 48, has been an almost constant campaigner for her husband and is comfortable on the stump as well as before cameras, such as when she appeared on ABC's "The View," where she talked about her family as well as her husband's policies.
"Michelle is a great asset, who talks about her daughters and leaving the world a better place for our [children] to have equal rights and equal opportunities," said Gandy.
Like Jackie Kennedy and Hillary Clinton, she has vowed to protect her two young daughters, Malia, 10, and Sasha, 7, from intrusive publicity, and that could shape her White House interests.
As a working mother, Obama's central theme could be balancing home and work. "How do contemporary women fulfill their own series while also fulfilling their desire for family?" asked Harris-Lacewell. "How do they support their husbands without getting lost in their identities?"
Harris-Lacewell also suggested that Michelle Obama may champion issues involving her children as they grow, such as gender equality and education.
Michelle Obama has hinted that she will have the first lady's office in the East Wing of the White House, where the family resides, and not in the West Wing, where government is carried out and where Hillary Clinton set up shop.
"My job is not a senior adviser," Michelle Obama has said.
But Michelle Obama has shown herself to be a hands-on person. She is a cum laude graduate of Princeton University and Harvard Law School. A former dean at the University of Chicago and currently a vice president at the University of Chicago Hospitals, she sits on six boards, including the prestigious Chicago Council on Global Affairs.
At the same time, however, Harris-Lacewell said Michelle Obama is cut from a "traditional mold."
"Michelle gave [Barack Obama] a sense of grounding and purpose in Chicago," said Anthony. "She gave him a sense of home."
There is a touch of "Jackie" in Cindy McCain, too, with her designer label outfits and perfectly coiffed appearance. But there is also a thread of steel running through her quiet demeanor.
Her mettle was on display eight years ago when her husband's challenge to George Bush was torpedoed in the South Carolina primary with a smear campaign that included the accusation that their adopted daughter from Bangladesh was the result of an affair McCain had had.
"Eight years ago, she had incredible dignity and was a fierce advocate of her own adopted daughter," Harris-Lacewell said. "She is a woman of more substance than people imagine."
Cindy McCain, 54, has also been battle hardened with her own personal disclosures. In 1994, she beat newspapers to the revelation that she had been addicted to painkillers Percocet and Vicodin after spinal surgery for ruptured disks. The addiction led her to steal drugs from her own nonprofit medical relief organization. She subsequently sought outpatient treatment.
She has gone on to use wealth inherited from her father to create a career in philanthropy.
McCain, who holds two degrees in education from the University of Southern California, serves as chairwoman of Hensley and Company, one of the largest beer distributorships in the country. She is, however, more hands-on in her philanthropy -- international work with Operation Smile and CARE. She also established her own nonprofit American Voluntary Medical Team, which sends medical teams to disaster or war-torn areas around the world.
She has been an elegant presence next to her husband on the stump but recently took on the high profile mission of traveling to the Georgian Republic after the Russia's invasion and meeting with President Mikheil Saakashvili. Earlier in the campaign, she made a very public tour of the children's charities she is involved with in Vietnam.
She has said that her overseas missions were an "important part of what I'm about, what makes me tick."
"Cindy McCain is an accomplished woman in her own right," Gandy said. "She manages a variety of enterprises. But I think she tries harder to fit into the more Republican mold of being the quiet, helpmate."
As a mother of four, she could have a more vocal role in her international charity work on behalf of children.
But Cindy McCain is not likely to be involved in her husband's administration. She told Harper's Bazaar, "I would not go to a Cabinet meeting. I don't deem it appropriate."
Cindy McCain is used to standing out. It is her inheritance that gives the McCain family its wealth; she is McCain's second wife and is quite a bit younger than her 72-year-old husband.
The fact that the family income comes from a beer distributorship and that the candidate for president has been divorced have not become issues.
"She's like Nancy Reagan, in the sense that she and Ronnie had been divorced," Berkowitz said. "Reagan made it a nonissue. She's from that world."
And her wealth is "relatively new money," Berkowitz said. "Having a beer distributorship, it's not unlike the Kennedy father. It's not like being a banker, not that respectability. It's more working class."